Monolithic and Microservices sample code examples in java

Category : Microservices | Sub Category : Microservices | By Prasad Bonam Last updated: 2023-07-11 08:54:14 Viewed : 350

Monolithic and Microservices sample code examples in java:

Here are simplified code examples in Java to illustrate the difference between a monolithic architecture and a microservices architecture:

Monolithic Architecture Example:

javaCopy code
// Monolithic application with a single class

public class MonolithicApp {

    public static void main(String[] args) {
        // Business logic
        UserService userService = new UserService();
        String message = userService.getUserMessage(123);
        System.out.println(message);
    }
}

class UserService {
    public String getUserMessage(int userId) {
        // Database access and business logic
        String userName = UserRepository.getUserName(userId);
        return "Hello, " + userName + "!";
    }
}

class UserRepository {
    public static String getUserName(int userId) {
        // Database query
        return "John Doe";
    }
}

In this example, the entire application is built as a single monolithic unit. The MonolithicApp class represents the entry point, and it directly calls the getUserMessage() method of the UserService class, which internally accesses the UserRepository to retrieve user information from the database.

Microservices Architecture Example:

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// Microservices-based application with separate services

// Service 1: User Service
public class UserService {

    public String getUserMessage(int userId) {
        // Call Service 2: User Repository Service
        String userName = UserRepoService.getUserName(userId);
        return "Hello, " + userName + "!";
    }
}

// Service 2: User Repository Service
public class UserRepoService {

    public static String getUserName(int userId) {
        // Database query
        return "John Doe";
    }
}

// Main Application
public class MainApp {

    public static void main(String[] args) {
        // Business logic
        UserService userService = new UserService();
        String message = userService.getUserMessage(123);
        System.out.println(message);
    }
}

In this microservices example, we have two separate services: the UserService and the UserRepoService. The UserService calls the UserRepoService to retrieve user information. Each service can be developed, deployed, and scaled independently. They communicate with each other through well-defined APIs, enabling loose coupling between the services.

Keep in mind that these examples are simplified for illustration purposes, and in real-world scenarios, the implementation and communication between microservices would involve additional complexity and considerations, such as using RESTful APIs or message queues for inter-service communication.